What is Lactobacillus rhamnosus GG?

What is Lactobacillus rhamnosus GG?

It’s one strain of a bacterium sold as a probiotic. Probiotics are live bacteria and yeasts said to have health benefits. They’re usually added to yoghurts or taken as supplements.

L. rhamnosus is the species. GG is the strain, one type within it. LGG is short for Lactobacillus rhamnosus GG.

Seen Lacticaseibacillus rhamnosus on a pack? It’s the same species under a new name. In 2020, scientists split the Lactobacillus group into 25 groups, and PubMed now files it as Lacticaseibacillus rhamnosus.

So check what you want it for, then check the strain code on the pack.

Does LGG help with diarrhoea from antibiotics?

In children, trials say yes. In adults, it’s less clear.

Antibiotics can cause diarrhoea. The NHS says this is usually mild and should pass once you finish the course.

But if you get diarrhoea while taking, or after, antibiotics, the NHS says ask for an urgent GP appointment or call 111. It can be a germ called C. diff.

A 2015 review combined 11 trials with 1,308 people, children and adults together. Diarrhoea fell from 22.4% without LGG to 12.3% with it. The quality of evidence was low.

Split by age, the drop was clear in 5 trials of 445 children. In 6 trials of adults, it was not significant, so it may have been down to chance.

The exception was a small group of adults taking antibiotics to clear H. pylori. That’s a germ that is one of the main causes of stomach ulcers. In 4 trials of 280 people, LGG did cut diarrhoea, but the evidence was low quality.

A Cochrane review of mixed probiotics in children found diarrhoea in 8% with probiotics and 19% without. It covered 33 studies and 6,352 children, with moderate certainty.

In a review of children on antibiotics, probiotics at 5 billion CFU a day or more worked better. CFU is a count of live bacteria. The review names L. rhamnosus as one example, and says a large trial is still needed to confirm it.

Trying it with a course of antibiotics? Look for GG on the label. Never stop or change a prescribed medicine without your prescriber.

Does L. rhamnosus help with stomach bugs?

Not in young children, in two large trials.

971 children aged 3 months to 4 years, brought to hospital emergency departments, had a tummy bug. A US trial gave them a 5-day course of LGG or a dummy pill. LGG did no better.

Diarrhoea lasted about the same, around 50 hours in each group.

A Canadian trial of 886 children seen in emergency departments tested a different strain, R0011, mixed with another bacterium. It did not prevent moderate to severe illness either: 26.1% against 24.7% on a dummy pill.

For a tummy bug, fluids come first. The NHS says the most important thing is lots of fluids to avoid dehydration. Don’t give children under 12 medicine to stop diarrhoea.

Why does the strain code matter?

Because trial results belong to one strain. What can differ between two rhamnosus packs is the strain code: the letters or numbers after the name, like GG or R0011.

Think of the species as a dog breed and the strain as one family line within it. A test on one line tells you about that line, not the whole breed. So a trial of GG tells you about GG, not every rhamnosus pack.

The 2015 review starts from the same point: the effects of probiotics are strain specific. The NHS says one type may help one problem, but that doesn’t mean other types will work just as well.

Probiotics are generally classed as food, not medicine. So the NHS says we can’t always be sure a pack holds the bacteria on the label. Or that it holds enough to have an effect, or that they survive to reach your gut.

For probiotics in general, see do probiotics work.

Is Lactobacillus rhamnosus safe?

For most people, yes. The NHS says probiotics appear to be safe for most people. If your immune system is healthy, they shouldn’t cause unpleasant side effects.

In the Cochrane review of children, side effects were 4% with probiotics and 6% without (low-certainty evidence). The common ones were rash, feeling sick, wind, bloating and constipation.

None of the 24 trials that reported side effects found serious ones caused by probiotics. But other studies have reported serious ones in very ill children, or children whose immune system is weak.

Your immune system is your body’s defence against germs. If yours is weakened, or you have a health condition, the NHS says talk to a doctor before any probiotic supplement.

A shop pack may not match the trials. The NHS says there’s likely to be a huge difference between trial-grade probiotics and those sold in shops.

Prefer food to pills? See fermented foods for gut health. For gut symptoms that won’t settle, see IBS blood tests.

When to speak to a GP

Diarrhoea usually stops within 5 to 7 days. A probiotic doesn’t replace getting help. Get help if:

• You have diarrhoea and you’re taking, or have recently taken, antibiotics. Ask for an urgent GP appointment or get help from NHS 111. C. diff, a germ that can cause diarrhoea, often affects people on antibiotics.
• You have bloody diarrhoea or bleeding from your bottom, diarrhoea for more than 7 days, or vomiting for more than 2 days. Call 111.
• You keep being sick and can’t keep fluid down, or (aged 5 or over) still have signs of dehydration after rehydration sachets. Call 111. Also call if you’re worried about a baby under 12 months, a child stops breast or bottle feeding while ill, or a child under 5 has signs of dehydration, such as fewer wet nappies.
• Call 999 or go to A&E if you or your child vomit blood or vomit that looks like ground coffee, or have green vomit (yellow-green or green in children). Also if you may have swallowed something poisonous, or have a stiff neck and pain when looking at bright lights.
• Call 999 or go to A&E too for a sudden, severe headache or tummy ache, or blue, grey, pale or blotchy skin, lips or tongue. On brown or black skin, this may be easier to see on the palms or soles. The same goes for severe trouble breathing, lots of quick, short breaths, or being confused or not responding as usual.